SNVAA80 July   2024 LM5177

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Reverse Current Operation
  6. 3Design Considerations
  7. 4Pin Configurations
    1. 4.1 Other Pin Configurations
      1. 4.1.1 MODE Pin
      2. 4.1.2 IMONOUT
  8. 5Application Measurements
  9. 6Summary
  10. 7References

4.1 Other Pin Configurations

For the reverse current operation, there are the following parameters, that need to be satisfied, for the typical operation of the LM5177 in reverse configuration.

  1. The LM5177 must be operated in FPWM. To enable this mode, voltages higher than 1.19V must be applied to verify that the Mode Pin is set to High.

  2. The device becomes enabled only, when the VIN voltage exceeds the internal VDET voltage.

  3. The output voltages of the converter must exceed the voltage threshold of the feedback pin (1.0V). If the output voltages are below the Feedback (FB) pin threshold, the converter functions in the standard forward mode.

  4. Several undervoltage protection schemes, like UVLO (for Output) and VDET (for Input), are available. Therefore, to allow reverse current operation and maintain device activation, the voltage at VIN and EN/UVLO must exceed the respective minimum programmed voltage thresholds.

To verify typical operation of the LM5177, at first, the device must be enabled by providing input voltages at Vin greater than the internal VDET Voltages. For this purpose, 5V is supplied at the input externally using a voltage supply, verifying that the input voltages are greater than the internal VDET voltages.